Direct Bonding Light Emitting Device Heat Dissipation
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Solution Overview
Problem
Existing light emitting devices face issues with heat dissipation and uniform chromaticity distribution due to the use of adhesives with low thermal conductivity, irregular atomic arrangements at bonding surfaces, and variations in component sizes, leading to reduced efficiency and potential damage from thermal stress.
Innovation Solution
A manufacturing method involving direct fixation of a translucent luminescent color conversion member to the light emitting elements, division into chips, and mounting on a substrate with a reflective member to facilitate heat dissipation and uniform chromaticity, using a double layer structure with light reflective and absorbing layers to control stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a light guide member made of adhesive is used to bond the light emitting element and the light transmitting member, then the bonding is achieved, but the thermal conductivity is low causing heat dissipation problems
Solution Approach 1:
The patent removes the light guide member made of adhesive from the structure. By directly bonding the light transmitting member to the light emitting element without an adhesive layer, the thermal conduction path is established directly, eliminating the thermal resistance introduced by the adhesive material while maintaining bonding functionality.
Solution Approach 2:
The patent introduces a reflective member as an intermediary component that serves dual functions: it reflects light to improve extraction efficiency and provides a thermal conduction path for heat dissipation. The reflective member is positioned to be in contact with both the light emitting element and the light transmitting member, creating an effective thermal bridge.
2Manufacturing precision
If the size of the light transmitting member is made greater than the light emitting element to ensure coverage, then mounting accuracy is improved, but uniform chromaticity distribution is compromised due to edge effects
Solution Approach 1:
The patent applies local quality by creating a size correspondence relationship between the light transmitting member and the light emitting element. The light transmitting member is designed to match the footprint of the light emitting element, ensuring that phosphor conversion occurs only in the region where light is emitted, thereby maintaining uniform chromaticity across the entire light output surface.
3Use of energy by moving object
If phosphors are used for luminescent color conversion, then color conversion efficiency is achieved, but heat generation occurs causing component deterioration
Solution Approach 1:
The patent converts the harmful heat generated by phosphors into a beneficial thermal conduction path. By establishing direct thermal contact between the light emitting element, reflective member, and light transmitting member, the heat that would otherwise cause component deterioration is efficiently conducted away, turning a harmful byproduct into an opportunity for improved thermal management.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively dissipates heat, improves luminescent color conversion efficiency, prevents component damage, and ensures uniform chromaticity distribution, suitable for applications like vehicle headlamps.
Implementation Method 1
a primary light (blue light) is an excitation light emitted from the light emitting element and a portion of the primary light is excited by the phosphors in the luminescent color conversion member to generate a luminescent color-converted (wavelength-converted) secondary light (yellow light)
Implementation Method 2
forming a reflective member including a light reflective material on the front surface of the mounting substrate, and surrounding and covering the light emitting element and the piece of the luminescent color conversion member by the reflective member
Implementation Method 3
the heat transfer to the light emitting element from the light transmitting member is blocked by the light guide member... the luminescent color conversion member is directly fixed to a light emitting surface side of the light emitting elements
Data Source
AI summary
In a method of manufacturing a light emitting device, a luminescent color conversion member made of a translucent material including phosphors is directly fixed to light emitting surface side of light emitting elements in a light emitting element group, and a stack of the light emitting element group and the luminescent color conversion member is divided into a plurality of chips. In each of the light emitting elements, a piece of the luminescent color conversion member is directly fixed to the light emitting surface of the light emitting element.